The present invention relates to an improved reverse flow cyclone separator and process for separating particulate matter from an influent raw gas stream.
Cyclone separators are well-known devices for removing particulates from a gas stream. In principle, a stream of particle-laden raw gas is introduced tangentially into a cyclonic separation zone so that the particles experience a centrifugal force in the ensuing swirling flow. The particles are collected on the outer wall of the separation zone and a resultant clean gas exits from a central exhaust duct.
It has been demonstrated that the performance of conventional reverse flow cyclones is typically reduced by a short circuiting of particulate laden raw gas from the cyclone inlet into the exhaust duct, thus bypassing the main body of the cyclone separator. An improved reverse flow cyclone separator described in U.S. Pat. No. 4,212,653 (Giles) avoids this source of performance degradation by employing a clean air shield between an influent raw gas flow and an outlet duct. Nevertheless, this improved cyclone separator still exhibits the centrifugal separation characteristic of decreased particle separation efficiency with decreasing particle mass. Accordingly, it is an object of the present invention to enhance the performance of reverse flow cyclone separators. More particularly, it is an object of the present invention to augment the centrifugal separation process characteristic of reverse flow cyclone separators through the employment of electrostatic forces. Correspondingly, it is a further object of the present invention to improve the separation efficiency of reverse flow cyclone separators, including an improved capacity to separate relatively small particulates from an influent raw gas stream.